This invention generally relates to apparatus for the preparation of a fluid sample upon a slide for microscopic analysis, and more particularly, to improved apparatus for supporting the slide and spreading the sample thereon.
Prior art devices have employed a base on which a slide to be stained is supported flat on a support surface thereof. A spreader is manually movable linearly relative to the base and engaging the surface of the slide with appreciable downward force so that the fluid sample can be spread over the slide to form a so-called "monolayer" of the sample. The spreader is intended to be disposable after each use thereof. Typically, a blood sample is spread into a monocellular layer on the slide which can then be microscopically examined for blood cell differential screening.
Several dificiencies exist in such prior art devices. As structured, the spreader frictionally engaged said support surface so that it formed grooves or ruts in the support surface of the base after multitudinous passes. Eventually irregularities in the path of the movement of the spreader relative to the slide actually interfered with uniformity of spreading of the sample and thereby prevented achieving the desired monocellular layer consistently with the same base which was not intended to be disposable. Also, the base tended to deform or flex downwardly because of the necessity to press downwardly on the spreader when making the monolayer. This deformation or flexing contributed to breakage of the slides on occassion as well as possible non-uniformity in monolayer spread of the sample on the slide.